The present invention relates generally to a milk tap assembly in a milking machine system, and particularly to a milk tap assembly for joining a teat cup unit to a system wherein a milk pipe is provided within a vacuum pipe.
Milking machine system of conventional design are constructed in such a way that milk and vacuum pipes are positioned about 1.5 meters above and parallel to the floor. This arrangement was intended mainly to protect milk pipes made of the glass from being kicked and destroyed by cows. However, with such a difference in height between the milk pipe and a teat cup unit affixed to the cow, vacuum pressure in milk lines associated with the teat cup unit changes as the milking operation proceeds. Thus, the vaccum pressure applied to the cow's teats changes every time the milk is sucked, and causes congestion about the teats or mastitides from the strong stimuli applied upon the lactic glandular cells. The conventional milk machine system generally is arranged as shown in FIG. 8 of the accompanying drawing, wherein a milk pipe 1 and a vaccum pipe 2 are positioned parallel to the floor and provided with a given number of tap boxes 3. A milk tube 4 is affixed to the box 3 at one end, and is connected at its other end with a milk claw 5 having a number of teat cups 6. A pulsator 7 is fixed to the tap box 3, and is interconnected with the vacuum pipe 2. Pulsator 7 and teat cup 6 are joined with a vacuum tube 8. In accordance with this construction, the milk tube 4 extends for a height H between the milk claw 5 of the teat cup 6 and the milk pipe 1 which transfers the milk. Thus, milk is not sucked immediately after attachment of the teat cups 6 to the teats. The vacuum in the milk pipe 1 works directly upon the teats via the milk tube 4 and the milk claw 5. When milk starts to flow out of the teats, passes through the milk claw 5 and begins to fill the milk tube 4, there arises a loss in vacuum when the milk tube 4 becomes completely filled with milk because of the height H of the tube. This acts to decrease the vacuum applied upon the teats of the cows. When the milking operation is over and no more milk is drawn into the teat cups, the vacuum then works on the teats in the same manner as when the operation began. Thus, the vacuum working on the teats changes from high to low and then again to high levels. A bleeder-hole is provided in the milk claw 5 to facilitate a smooth flow of milk by allowing air to enter into the milk tube 4 to prevent the tube from becoming overly full with milk. In the case where the height from the milk calw 5 to the milk pipe 1 is 1.5 meters, the vacuum within the milk pipe 1 is usually 380 mm Hg. However, when the milk tube 4 is filled with milk, there will be a loss of about 110 mm Hg so that the vacuum working on the teats decreases to 270 mm Hg. In this manner, the vacuum changes from 380 to 270, and back to 380 mm Hg during the milking operation. If these variations continue, the area around the teats will become congested and the orifice of the lactic canal will project and turn outwardly, thereby increasing susceptibility to germs and to sicknesses.
An object of the present invention is to obviate the above defects in the prior milking machines and to prevent injuries to the teats of milking cows.
In accordance with the present invention, a milking machine tap arrangement for connecting a teat cup unit with a milk pipe and a vacuum pipe comprises a tap box unit including a housing having a window opening in an axially extending side wall, and two axially aligned connecting tubes extending from opposite ends of the housing for providing air tight connections with axially spaced sections of a vacuum pipe. A tubular tap body is located within the housing and has its axially spaced ends connected with axially spaced sections of milk pipe which extends within the vaccum pipe. A first port is arranged on the side wall of the tap body to allow communication with the milk pipe through the tap body, the first port facing the window opening. A tap frame is fixed to the housing over the window opening, and an air packing is mounted to the tap frame to form a second port which allows communication with the vacuum pipe through the interior of the housing. A gate is slidably mounted to the frame for simultaneously closing the first and second ports.
The various features of novelty which characterize the invention are pointed out with particularly in the claims annexed to and forming a part of this disclosure. For a better understanding of the invention, its operating advantages and specific objects attained by its use, reference should be had to the accompanying drawings and descriptive matter in which there are illustrated and described preferred embodiments of the invention .